The invention relates in general to munitions and in particular to shouldered firearms.
The M4 Carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16. The M4 is a shorter and lighter version of the M16. The M4 is gas-operated, air-cooled and magazine-fed. The M4 has selective fire options including full automatic and semi-automatic.
One primary difference between the M4 Carbine and M16 weapon systems is the increased velocity of the M4 bolt carrier. For the M4 Carbine, the higher bolt opening and closing velocities translate to higher cyclic rate and bolt durability problems due to high stress on bolt lugs. Additionally, instances of misfires are increased due to “bolt bounce”. Bolt bounce refers to the bolt carrier hitting the barrel with enough velocity so that the bolt carrier rebounds into the path of the hammer. Also, the elevated cyclic rate of the M4 Carbine contributes to feeding problems because the ammunition does not have enough time to properly position itself into the correct location before the bolt carrier interfaces with the round. There is a need to eliminate these problems.